**Text Transcription**B) Because this arm is in equilibrium, you can pick any axis of rotation you would like. On the picture above identify an axis of rotation that reduces the number of unknowns in the torque equation you will create for part C).C) Write down the equation that results from the fact that the "Net external torque (for the axis you chose in part B) must be zero" on this arm.**Additional Explanation for Educational Use**- *Equilibrium and Torque:* Equilibrium means the arm is not rotating, and the net external torque must be zero. Torque is the rotational equivalent of force and depends on the force applied, the distance from the axis of rotation, and the angle between the force and the lever arm. - *Choosing an Axis of Rotation:* Selecting an axis where multiple unknown forces intersect can simplify calculations. By doing so, certain forces will exert no torque because the distance to the axis is zero, effectively reducing the number of unknowns.- *Writing the Equation:* Analyze the forces acting at different points on the arm. Use the relationship for torque, \(\tau = r \times F \times \sin(\theta)\), where \(r\) is the lever arm, \(F\) is the force, and \(\theta\) is the angle. Set the sum of all torques to zero to solve for unknowns. **Title: Analyzing Forces in the Human Arm****Introduction:**In figure P8.7, we examine the forces acting on a human arm. This image is used to understand the physical principles involved when an arm is extended.**Text Description:**The arm depicted in figure P8.7 has a weight \( F_g = 41.5 \, N \). The weight of the arm acts through point A as shown.**Diagram Explanation:**- **Arm Illustration:** The arm is extended horizontally, and the forces acting upon it are illustrated with vectors. - **Forces:** - \( \vec{F}_t \): This is the tension force vector acting at an angle of \( 12^\circ \) from the horizontal. The vector points away from point O, indicating the direction of the tension. - \( \vec{F}_s \): This force acts at an angle \( \theta \) downwards from point O, representing the stabilizing forces required to maintain the arm's position. - \( \vec{F}_g \): This is the gravitational force acting downwards at point A, representing the weight of the arm.- **Measurements:** - The distance from point O to point A is \( 0.290 \, m \). - The distance from point O to where the stabilizing forces (\( \vec{F}_s \)) act is \( 0.080 \, m \).**Reference:**This illustration is sourced from "P8.7 from Serway and Vuille 9th Ed."**Concluding Notes:**Understanding the interaction of these forces provides insight into biomechanics and the physics behind human movement.

(B) In order to reduce the number of unknowns, the pivot point is chosen at the point of action force with maximum number of unknowns Now consider an axis of rotation about point O. The force acting at that points has two unknowns, both magnitude and direction. Whereas at the point between O and A, only the magnitude of the force is unknown. Thus, an axis about point O is considered the axis of rotation.(C) Net torque about point O τO=0Ftrtsin12°-Fgrg=0Ft=Fgrgrtsin12°=41.5 N0.290 m0.080 m=150.4 N≈150 N

Answered: Because this arm is in equilibrium, you…